Adaptational Villainy: This version of Scrooge comes across as a great deal colder than most. Rather than his usual indifferent self he seems to actively take pleasure in the suffering of others. He also makes more efforts to defend himself to the spirits than most versions.
George C. Scott's Scrooge is just as compelling for his originality as his believability. For starters, there's the above-mentioned Adaptational Villainy and coldness, with the fact that he even smirks and laughs in disdain at others' kindness and Christmas cheer. He's also much more of a "tough nut to crack" than other Scrooges, responding to the ghosts' revelations with a blend of self-defense, denials and Don't You Dare Pity Me!, even as he's clearly shaken and softening, until the moment when he finally vows to change and collapses in Broken Tears at his own grave. Last but not least, his post-Heel–Face Turn manner is less wildly giddy than others (apart from one adorable moment of gleefully jumping on his bed), but blends joy and warmth with the same reserve and dignity he had before, as well as a due sense of regret and apology for his past actions.
The Ghosts of Christmas Past and Present are both more Cruel to Be Kind than usual. Past responds with smirking sarcasm to Scrooge's attempts to defend his mistakes, while Present is possibly the angriest portrayal of that spirit ever put to screen.
David Warner's Bob Cratchit is less meek and pathetic than many other portrayals and more of a stolid, quietly dignified Iron Woobie, which makes it especially heartbreaking when he finally breaks into Manly Tears over Tiny Tim's death.
A minor example with Belle. Instead of being The Cutie/The Ingenue as per her standard characterization, she comes off much more strong-willed and bitter about Scrooge's neglect. When she asks Scrooge if he'd still try to win her now if he hadn't originally engaged with her, he attempts to mask his dithering by accusing her of doubting that he would. In the book, she lets the comment slide; here, Belle calls him out on his Revealing Cover-Up, implying that this above all was proof that their romance really is over. She still feels sympathy for him years later, though, when she learns from her husband how alone he is.